Flexible electrical connector assembly



April 10, 1956 E. F. MEKELBURG 2,741,753

FLEXIBLE ELECTRICAL CONNECTOR ASSEMBLY Filed Feb. 3, 1953 4 ill W O 15:: 7 S C) Q\ I Q if rm 0 w J INVENTOR. .ZZr/ff/Vie/Zzz7 United StatesPatent FLEXIBLE ELECTRICAL CONNECTOR ASSEMBLY Earl F. Mekelburg,Wauwatosa, Wis., assignor to Square D Company, Detroit, Mich, acorporation of Michigan Application February 3, 1953, Serial No. 334,863

7 Claims. (Cl.-339276) This invention relates to an assemblyincluding arelatively rigid conducting part and an associated flexible electricalconnector.

ln-the past, movable contact fingers carrying the movable contact of anelectrical device have been electrically connected to fixed parts byflexible, stranded electrical.

connectors, frequently referred toas pigtails, these flexible leadsbeing connected to the fixed and movable members by means of welding,brazing, riveting, or the like.

It has been found that such prior mechanisms are frequentlyunsatisfactory in that the movement" of the movable contact fingercauses a loosening and eventual rupturing of the point of connection ofthe flexible lead. In addition, the prior means of connection to whichreference has been made above were more expensive than would be desired.

Furthermore, in other assemblies comprising relatively rigid conductingparts and associated flexible electrical connectors the above, andother, difficulties were encountered. lt is, therefore, one object ofthe present invention to provide an assembly comprising a flexibleconductor and an associated conducting part of improved design which isinexpensive to fabricate.

Another object of the present invention is a device in accordance withthe preceding object in which the mechanical and electrical connectionbetween the flexible lead and its associated parts is of improvedcharacter.

Other objects and features of the invention will be readily apparent tothose skilled in the art from the specification and appended drawingillustrating certain preferred embodiments in which:

Figure l is a bottom view of a contact finger and lug assembly inaccordance with the present invention.

Figure 2 is a side view of the device of Figure 1.

Figure 3 is a plan view of the contact finger and lug of Figures 1 and 2prior to assembly.

A specific embodiment of the present invention comprises a contactfinger 1 of copper, bronze, or other suitable material familiar in theelectrical art having electrical contacts 2 mounted upon one end portionthereof by means of nuts 3 or other suitable fastening means. Theopposite end portion of the contact finger 1 is provided with apertures4 through which extend end portions of stranded, flexible electricalconductors, or pigtails, 5.

The opposite end portions of the conductors 5 extend through suitableapertures 6 in 0. lug 7. As may be seen from Figure l, the surfacesforming the apertures 4 and 6 tightly engage the associated end portionsof the flexible leads 5 whereby an excellent mechanical and electricalconnection is efiected between these flexible leads and the associatedstructure.

Prior to the assembly of the various patrs, the contact finger 1 and thelug 7 have the form indicated in Figure 3. End portions of the flexibleleads 5 are then inserted through the apertures 4 and the sides of thecontact finger 1 are compressed in a swaging die or other suitabledevice until the parts assume the shape indicated in Figure 1.Similarly, the opposite end portions of leads 5 are inserted throughapertures 6 and the sides of lug 7 are suitably compressed. It will beobvious that an excellent electrical and mechanical connection betweenleads 5 and the associated parts is thus effected.

As will readily appear, the present invention provides a simple andeconomical contact finger and lug assembly in which the flexible leadsare connected to both the fixed lug 7 and the movable contact finger 1with a connection which is excellent both electrically and mechanically.

It will be obvious that the lug 7 may be composed of copper, brass orother similar conducting material, and it will further readily appearthat the amount which the flexible leads extend through the variousparts with which they are associated, and the degree to which theseparts are compressed to hold the ends of the flexible leads firmly inplace, may be appropriately varied to fit the demands of any particularapplication.

While a certain preferred embodiment of the invention has beenspecificably disclosed, it is understood that the invention is notlimited thereto, as many variations will be readily apparent to thoseskilled in the art and the invention is to be given its broadestpossible interpretation within the terms of the following claims:

What is claimed is:

1. A contact finger assembly comprising a contact finger ofsubstantially rigid and conducting material having an aperture extendingthrough said contact finger, a flexible electrical connector having oneend portion extending through said aperture with the surfaces of saidcontact finger which form said aperture deformed at least in part totightly engage said end portion of said flexible electrical connectorwhereby said flexible electrical connector is electrically andmechanically connected to said contact finger, a lug of substantiallyrigid and conducting material with an aperture extending through saidlug, the opposite end portion of said flexible electrical connectorextending through said lug aperture with the surfaces of said lug whichform said lug aperture tightly enga ing said opposite end portion ofsaid flexible electrical connector whereby said flexible electricalconnector is electrically and mechanically connected to said lug andsaid contact finger and lug are interconnected.

2. A contact finger assembly comprising a contact finger ofsubstantially rigid and conducting material having a plurality ofapertures extending through said contact finger, a plurality of flexibleelectrical connectors having end portions extending through saidapertures with the surfaces of said contact finger which form saidapertures deformed at least in part to tightly engage said end portionsof said flexible electrical connectors whereby said flexible electricalconnectors are electrically and mechanically connected to said contactfinger, a a substantially rigid and conducting material having aplurality of apertures extending through said lug, the opposite endportions of said flexible electrical connectors extending through saidlug apertures with the surfaces of said lug which form said lugapertures similarly deformed to tightly engage said opposite endportions of said flexible electrical connectors whereby said flexibleelectrical connectors are electrically and mechanically connected tosaid lug and said lug and said contact finger are interconnected, and atleast one electrical contact mounted to said contact finger at a pointspaced from the point of connection of said contact finger to saidflexible electrical connectors.

3. The method of electrically and mechanically connecting a flexibleelectrical connector to a substantially rigid conducting part comprisingforming an aperture through said conducting part with an axisperpendicular to a major surface of the part and with the apertureadjacent a side edge of the part, inserting in said aperture the end ofa flexible connector of a cross-sectional area less than thecross-sectional area of the aperture, and deforming the material of thepart between the aperture and said side edge to decrease thecross-sectional area of the aperture and compress the connector therein.

4. The method of electrically and mechanically con meeting a flexibleelectrical connector to a substantially rigid conducting part comprisingpiercing an aperture through said conducting part adjacent to a sideedge thereof and substantially normally to a major surface of said part,inserting through said aperture an end portion of a flexible connectorhaving a cross-sectional area less than that of the aperture, andforcing the side edge of said conducting part adjacent said apertureinwardly a sufiicient amount to decrease the cross-sectional area ofsaid aperture and tightly compress the end portion of said connectorinserted therethrough.

5. The method of electrically and mechanically connecting a flexibleelectrical connector to a substantially rigid conducting part comprisingpiercing an aperture through said conducting part adjacent to a sideedge thereof and substantially normally to a major surface of said part,inserting through said aperture an end portion of a flexible connectorhaving a cross-sectional area less than that of the aperture, andswaging said conducting part to deform the material thereof between theaperture and said side edge sufiiciently to decrease the cross-sectionalarea of said aperture and tightly compress the end portion 30 of saidconnector inserted therethrough whereby the electrical and mechanicalconnection of said flexible connector to-said conducting part iseffected.

6. An assembly comprising means of substantially rigid and conductingmaterial having an aperture transverse to a major plane thereof andextending therethrough adjacent an edge thereof so that the length ofthe aperture is substantially the same as the thickness of saidmaterial, a flexible electrical connector having one end portionextending through said aperture, the edge of said means being pressedinwardly adjacent to the aperture to deform at least in part thesurfaces which form the aperture to tightly engage said end portion ofsaid flexible electrical connector whereby said flexible electricalconnector is' electrically and mechanically connected to said means.

7. An assembly comprising means of substantially rigid and conductingmaterial having an aperture extending therethrough which issubstantially perpendicular to a major surface of said means anddisposed adjacent to an edge thereof, a flexible electrical connectorhaving one end portion extending through said aperture, the edge of saidmeans adjacent to said aperture being pressed inwardly to deform atleast in part the surfaces which form said aperture to tightly engagesaid end portion of said flexible electrical connector whereby saidflexible electrical connector is electrically and mechanically connected to said means.

References Cited in the file of this patent UNITED STATES PATENTS2,555,075 Bergan May 29, 1951

